The present invention pertains to a process and a device for fastening a cap on a container, wherein the container and the cap are provided with engaging means cooperating for the purpose of fastening. The present invention pertains, in particular, to the fastening of a turn cap.
Prior-art devices for fastening a screw cap on a container, e.g., a tube, are designed as shown in FIG. 1. A tube 1 is positioned by a mandrel acting as a positioning means 3 in a defined starting position and is set into a rotary movement around its own longitudinal axis in this starting position. A turn cap 2 for the tube 1 is held by holding pliers 4 in a starting position positioned accurately in relation to the tube. The screw threads of the tube 1 and of the turn cap 2, which are to be screwed together, are located exactly flush with one another in this starting position. The holding pliers 4 are linearly displaced from the starting position toward the tube 1 along the axis of alignment A of the two screw threads by means of a corresponding drive means. In the course of the fastening, the holding pliers 4 first move toward the tube 1 with the turn cap 2, clampingly holding it. After the tube 1 and the cap 2 or its screw thread have engaged one another, a further displacement of the turn cap 2 is brought about by the screwing that is now beginning. The starting position of the tube 1 and the turn cap 2 is shown in the top part, and the end position after the fastening is shown in the bottom part of FIG 1. In this end position, the tube 1 and the turn cap 2 are connected in a positive-locking manner and preferably also in a non-positive manner with a defined tightening torque.
When this predetermined tightening torque has been reached, the turn cap 2 is rotated further by a small amount in relation to its holding pliers 4, as a result of which the surface of the turn cap 2, which is usually coated, may be damaged.
EP 0 205 803 A1 describes a device in which a rotating drive of the screw head and a holding means directly holding the turn cap are connected to one another in a screw head forming the holding means via a flexible torsion coupling to prevent excessively strong tightening torques. The torsion coupling absorbs the rotation energy of the mass, which continues to rotate and is formed by the container and the turn cap, and guarantees as a result a so-called soft screw drop during the screwing on of the turn cap. The risk of damage to the surface of the turn cap is reduced, but not eliminated altogether. A requirement that the turn cap must be in an accurate rotary position in relation to the tube may also cause problems.
The primary object of the present invention is to fasten a cap on a container such that the cap will not be damaged during the fastening.
According to the invention, a device for fastening a cap on a container is provided, wherein the container and the cap are provided with engaging mechanism cooperating for the purpose of fastening the two with respect to each other. The device includes a positioning mechanism for the container. A holding and positioning mechanism is provided with a clamping holding mechanism, which clampingly holds the cap and positions same in a starting position in relation to the container. The positioning mechanism and the holding and positioning mechanism engage the container and the cap with one another and connect them to one another in a positive-locking manner and preferably also in a non-positive manner by a forced relative movement. The holding and positioning mechanism comprises a non-clamping holding mechanism, which is fastened to the positioned cap. The non-clamping holding mechanism is movable in relation to the clamping holding mechanism.
According to another aspect of the invention, a process is provided for fastening a cap to a container. The cap and container are provided with an engaging mechanism cooperating for the purpose of fastening, in which. The process includes positioning the container and the cap in a starting position in relation to one another and they are subsequently connected to one another in a positive-locking and preferably also non-positive manner. The cap is held by a clamping grip during the positioning. The positioned cap is taken over by a non-clamping holding mechanism and the clamping grip of the cap is released before the positive-locking and preferably also non-positive connection is made.
The present invention is based on a container, e.g., a tube, can, bottle or the like, and a cap therefor, which are provided with cooperating engaging mechanism for the purpose of fastening or attaching the cap to the container. The cap is preferably a turn cap and the engaging mechanism are screw threads or an engaging mechanism of a bayonet catch. However, the present invention may also be applied, in principle, to other caps and engaging mechanism in which the cap is, e.g., pushed simply onto the container and the positive-locking and preferably non-positive connection is established by simple wedging or locking; even though the container and the cap would possibly be connected to one another in a positive-locking manner only in the latter case, there would be a combined positive locking and nonpositive locking up to the locking proper.
For the purpose of fastening, the container and the cap are first positioned in a starting position in relation to one another. A relative movement between the container and the cap will subsequently take place from the starting position, the cap being connected and fastened to the container in a positive-locking and non-positive manner at the end of this relative movement. For positioning, the cap is held by a suitable holding mechanism by means of a clamping grip. The holding mechanism used to position the cap is hereinafter called correspondingly a clamping holding mechanism or clamping holding means.
The positioned cap, i.e., the cap being held in a defined starting position in relation to the container by the clamping holding mechanism, is taken over according to the present invention by a non-clamping holding mechanism or non-clamping holding means and the clamping grip of the clamping holding mechanism is released after the take-over. Since the take-over takes place in a defined position of the cap, the taking-over holding mechanism, which preferably holds the cap until the completion of the fastening, may be formed by a non-clamping holding mechanism. The risk of damage to a coated surface of the cap at the end of the fastening operation due to the tightening torque to be applied is effectively reduced as a result; damage is avoided in practice, because a holding grip of the cap takes place in a non-clamping manner at this critical moment.
A device that is especially suitable for carrying out the above-described process has a positioning mechanism or positioning means for the container as well as a holding and positioning mechanism or means for the cap, which comprises the clamping holding mechanism, which clampingly holds the cap in the defined starting position in relation to the container.
According to the present invention, the holding and positioning mechanism or means comprises, in addition to the clamping holding mechanism, the non-clamping holding mechanism, which is fastened to the positioned cap, i.e., the cap still being held by the clamping holding mechanism. The non-clamping holding mechanism is movable according to the present invention together with the cap in relation to the clamping holding mechanism. The clamping grip, by which the clamping holding mechanism has held the cap in the starting position until secure take-over by the non-clamping holding mechanism, is released.
The non-clamping holding mechanism preferably has a contact piece fastened to the cap in a manner secured against rotation and displacement and a connection piece, which is in turn fastened to a platform, which is preferably arranged movably in relation to a frame of the device. The platform may be formed, in principle, by the frame itself In the case of stationary arrangement of the non-clamping holding mechanism, the container would be able to be moved out of the starting position toward the cap.
To fasten the cap on the container with a defined tightening torque or a defined tightening force, as a result of which an initially purely positive-locking engagement between the container and the cap becomes a positive-locking and non-positive connection, the contact piece of the non-clamping holding mechanism is connected to the connection piece in an articulated manner, preferably by mechanism of a pivot bearing, and a coupling, preferably a friction coupling, which is pressed against the contact piece with a frictional force corresponding to the tightening torque or the tightening force, prevents a movement of the articulated connection and consequently a relative movement between the contact piece and the connection piece. As soon as the desired tightening torque or the desired tightening force is reached, the frictional coupling releases the rigid connection between the contact piece and the connection piece or the platform, as a result of which a further relative movement between the container and the cap is prevented. Simultaneously with the elimination of the rigid connection between the contact piece and the connection piece or the platform, the fastening of the contact piece on the cap is preferably eliminated as well.
The non-clamping holding mechanism may be connected to the cap in a purely positive-locking manner, but this requires a corresponding preparation of the cap. It would also be possible to use, quite generally, a holding magnet, e.g., in the case of metallic caps.
In a preferred embodiment, the non-clamping holding mechanism is a suction-type holding mechanism with a suction tube, which is directly attached to the cap and is fastened by mechanism of suction force.
Not only damage-free fastening is achieved if the non-clamping holding mechanism is designed as a suction-type holding mechanism. Since the suction-type holding mechanism can be arranged in an especially simple manner on a rear face of the cap, its use is also possible independently from the shape and the surface finish of the outer jacket surface of the cap. Since the clamping holding mechanism also needs to hold the cap in the starting position, adaptation to different jacket shapes of the cap is also possible in a simple manner.
Furthermore, if a frictional coupling is arranged, it is achieved with a particularly simple design that the cap can be fastened to the container accurately in terms of the angle of rotation and with a defined tightening torque or a defined tightening force.
However, accurate fastening in terms of the angle of rotation with a simultaneously accurate setting of a desired tightening torque or a desired tightening force is also facilitated, in principle, by the use of a non-clamping holding mechanism. If the non-clamping holding mechanism is designed, in particular, preferably as a suction-type holding mechanism, this can be achieved by the fastening of such a suction-type holding mechanism, which fastening is detachable quasi free from distortion when the desired tightening torque or the desired tightening force is reached.
The container is a tube, can, bottle, glass jar or the like, preferably from the field of the food industry, hygiene, cosmetics or medicine. The containers for whose closure the present invention is preferably used are, e.g., tubes for pastes, such as toothpaste, ointments and foods in the form of pastes, bottles for beverages, glass jars for jams or even small perfumery bottles.
Preferred embodiments of the present invention will be described below on the basis of FIGS. 2 and 3.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated.